History of diatom research in South Africa

Diatom research in South Africa can be divided into five distinct periods. The first period covers a span of some seventy years, beginning with Shadbolt’s (1854) account of the diatoms from Port Natal, and continuing with brief reports and notes on odd specimens found in various samples sent to the leading diatomists of the day (e.g. Cleve 1894 and 1895; Grove, 1894).

The second period spanned the time between the two world wars and is characterised by accounts of diatoms found in the more general algological surveys made by a number of algologists, notably Felix Eugen Fritsch, Florence Rich and Edith Stevens (e.g. Fritsch and Rich, 1924, 1930).

The third period involved the most comprehensive study of diatoms in South Africa, and commenced after the arrival of Dr Bela Jeurno Cholnoky in South Africa in 1952. Cholnoky was a Hungarian refugee whose chief interest in life was the diatoms. Through his intensive and extensive taxonomic and ecological studies he built up the diatom collection of the then National Institute for Water Research (CSIR) in Pretoria, making it the centre for diatom research in this country. Cholnoky placed little faith in only the chemical analysis of water quality, arguing forcefully that the chemical and physical characteristics of a water body could be determined more reliably and easily through a study of the diatom associations found living in it (Cholnoky, 1968). His diatom investigations focussed, therefore, on two aspects – the taxonomy of the diatoms and their species specific autecology.

During this third period he also trained his successors, Dr R. E. M. ‘Archie’ Archibald who became his assistant in 1964; Dr Ferdi Schoeman who joined the institute in 1968; and Prof Malcolm Giffen of the University of Fort Hare. Dr Archibald and Dr Schoeman were trained in the ecology and taxonomy of freshwater diatoms while Prof Giffen was encouraged to study marine littoral and estuarine diatom taxa.

Following the death of Cholnoky in 1972, the fourth period saw a very fruitful partnership between Dr Archibald and Dr Schoeman in which new approaches to the taxonomy of diatoms were made, culminating in the production of “The Diatom Flora of Southern Africa”(Schoeman and Archibald, 1976- 1981). For each species included in this flora, samples of the type material were obtained and examined using traditional light microscopy techniques as well as electron microscopy. In this way the authors were able to check their identifications and fix the concepts of species according to their own observations of the type material. The resulting detailed descriptions and commentaries on each species, together with the first attempts to produce a diatom atlas correlating drawings, and both light and EM

photomicrographs earned high praise for the first six parts of this Flora. Unfortunately, the thorough treatment of each species was considered to be excessively costly and time consuming, resulting in the Flora being discontinued.

After the curtailment of the Flora there was a shift in the direction of diatom studies at the NIWR, and two lines of research were followed. The first of these adopted a purely taxonomic direction of study in which selected species were individually examined and thoroughly revised in the light of both type material and local material. Special attention was focussed on the genus Amphora, but other species in other genera were treated when and if material became available. The second line of research returned more to the style of investigation used by Cholnoky in his surveys from different regions but incorporated the new developments in electron microscopy and photomicroscopy.

At the end of 1986 Dr Schoeman left the NIWR, bringing to an end a fruitful partnership, in which he was the co-architect of so much that was achieved for over a decade. Continuing on the foundation laid by Cholnoky, the NIWR group had developed into the largest diatom research centre in the Southern Hemisphere at that time. Details of this collection have been discussed in Harding et al. (2004).

The third and fourth period of diatom research at the NIWR(CSIR) saw the strength of human resources engaged in diatom work rise from one to four full-time researchers as well as several for whom diatoms were a secondary interest, then decline again to one person, Archie Archibald, occupied full time with the help of an assistant. Following the untimely death of Dr Archibald in December, 1999 meaningful diatom research ceased at the CSIR. The Diatom collection was subsequently transferred to the CSIR in Durban under the care of Colin Archibald before his retirement in 2002.

The fifth or current period of diatom research in South Africa includes research undertaken under the leadership Prof Guy Bate (University of Port Elizabeth now Nelson Mandela Metropolitan University) which commenced with a study of diatoms in South Africa in the late 1990’s. The research focussed on the ecological aspects of diatom assemblages for determining water quality and attempted to apply a descriptive European diatom index for South African conditions (Bate et al, 2002). This research continued with the publication of a Water Research Commission report relating freshwater, brackish and estuarine species to key water quality variables (Bate et al., 2004).

Also during this same period Dr Bill Harding commenced with an evaluation of the ex NIWR (now CSIR-Environmentek) diatom collection, as well as initiating further diatom studies by producing a set of protocols (of which this volume forms a part) by which diatom samples can be collected, prepared and the species in the samples identified – and by the use of which diatoms can form a valuable component of biomonitoring in South Africa. Diatom studies have also been undertaken in the last five years at the North-West University (Potchefstroom

Campus) where the application of numerical diatom indices to South African rivers was tested (Taylor, 2004). Other students are now engaged in both diatom ecological and taxonomic studies at M.Sc. and Ph.D. level. This revival of interest in the diatoms together with the production of standard protocols and the rigorous testing of numerical diatom-based indices, should culminate in the realisation of Cholnoky’s prediction that diatom associations can be used to give a reliable and accurate indication of the chemical and physical characteristics of a water body.